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Potential “smoking gun” for life on Mars

By using methane concentrations beneath a Greenland glacier, scientists …

Mars landers have found varying concentrations of methane on the red planet. Determining what is producing this methane has been a point of contention in the scientific community for a few years. On Earth, most of the methane in our atmosphere is produced by naturally-occurring methanogens. Methanogens—anaerobic bacteria that grow in areas devoid of oxygen—thrive in some pretty unusual places: cow rumen, at the bottom of swamps, and under glaciers—like the one studied in Greenland.

In ice cores taken from the glacier, Dr. Price of UC Berkeley found unusually high levels of methane in the ice core. In some cases, levels were 10 times what was expected.

The potential "smoking gun" behind the study is due to two related factors. First, methanogens would thrive at temperatures of about 18F, if they exist. To get to soil that is 18F, a probe would have to drill about 1,000 feet into Martian soil. For an unmanned mission to the red planet, this is a tall order. However, by choosing a meteor crater on Mars where methane concentrations are higher than normal, scientists could analyze the soil brought to the surface by the meteor impact. In theory, there should be about 1 mostly-frozen methanogen for every cubic centimeter of soil analyzed. Analyzing the soil this way is well within the capabilities of current technology.

UV light from the sun breaks down methane constantly. Because concentrations on Mars are what they are, the methane is being replenished all the time. What is also interesting is that these areas of higher methane concentration coincide with areas of higher water vapor concentration in the Martian atmosphere. The question that has to be answered now is whether microbial life is creating the methane, or if it's occurring as a byproduct of a non-biological reaction between rocks and the Martian atmosphere, or volcanic outgassing. In any event, I think it's a safe bet to say that one of the next Martian probes will attempt to answer this question once and for all, using the methods outlined by Dr. Price.